White Spot Syndrome Virus (WSSV) is the infectious agent causing deadly disease in marine crustaceans, particularly prawn or shrimp of the Penaeidae family. WSSV is extremely virulent that prevention and inhibition of its spread in an aquaculture farm seems impossible once settled. The infected prawns have white spots developed on the carapace, appendages and cuticle. Rapid reduction in food consumption among the infected prawns is common phenomenon. The disease can lead up to 100% mortality in a commercial shrimp farm within 7 to 10 days. Researches have been carried out in years to find an effective treatment to cure or prevent the disease. Many of these researches focus on employing the antigenic peptides of the WSSV, particularly envelope protein VP28 and VP19 or nucleocapsid proteins VP26 and VP24, to prophylactically immunize the crustacean against the WSSV infection before the actual infection occurred.
For example, U.S. Pat. No. 7,749,506 describes cloning and expression of different antigenic WSSV proteins in a host cell in order to produce vaccine constituted of the produced antigenic peptides. Another United States patent with publication no. 2008/0107652 discloses development of WSSV's antibody in microalgae Dunaliella that the microalgae containing the antibodies is fed to the crustacean to prevent, ameliorate or treat the WSSV disease.
International patent with publication no. 2004083893 provides cell surface expression vector comprising genetic sequence encoding antigen of WSSV and gene of a poly-gamma-glutamate synthetase complex as the expression marker. The vector is hosted in a bacterium for producing the antigen which can be subsequently processed for preparing vaccine or feedstuff additive to prevent or cure the disease.